Hi guys, a few of you might have seen my build in the single turbo section, if you wanna have a read it should give you an idea of what the car is built for.


Since the car will run 50psi base pressure of fuel and the engine will need 6000cc/min of fuel at peak power i worked out id need 360 litres per hour worth of pumping power.

now pumps that you see the specs for arnt rated for that certain fuel pressure.

A 305LPH flows 230LPH at 50psi so im gonna run 2 pumps to give 460LPH

These are gonna be both intank strapped together

ill be using a Y piece to connect the to pumps together inside the tank....2x -6 to a -8 Y piece

Then -8 fuel line running to a -8 fuel filter, then -8 fuel line to a Y piece with 2x -6 to split to the 2 fuel rails.

the primary rail will be running the original 550cc injectors(obviously at 50psi fuel pressure they will be higher, maybe 600cc)

the secondary rail will be running ID 2200cc injectors(at 50psi will be 2500cc)

the reverse will be the same as above as a Y piece will connect them back up together before heading to the FPR, that line will be -8

Through the FPR and a -8 return line back the tank.


I know that might not be written very well but this is my first go at setting up a fuel system and im not really sure the easiest way to explain it so i have included a picture.




If someone can give me some pointers and see if theres anything i have done wrong i would really appreciate it

 

I would not run -4 to the primary rail as it is way too small, go with the -6 to keep it balanced with the secondary. Actually, I would run -8 for the whole system. I also would not join them back together prior to the FPR. If you are using the Aeromotive FPR it has two ports, one for each line, then a return port out the bottom

 

ok thanks very much for the info

I was gonna go for a aeromotive FPR and run both the ports but this was just for my stock injectors/rail/fpr and then add the other stuff later.

If i went for -8 for the whole setup what do i have to do with rails, get them specially made so its -8 all the way through the rail, ie no restriction inside the rail itself.

Im not really sure who to buy from, i was thinking of keeping my stock primary rail then putting 850cc in there as someone in the UK mentioned stock 550cc risk getting stuck open above 45psi of fuel pressure

 

Give Jon from AtomicRex a ring - He will sort you out and answer any of your questions

0870 903 6666

 

You lost me...

That drawing will not work at all for the stock rails, injectors and FPR. The stock FPR is attached to the secondary rail.

Now whoever told you the stock 550cc injectors get stuck open above 45psi does not know what they are talking about. The base fuel pressure is 40psi, with stock boost it gets raised to 50psi. So with the sticking at 45psi wisdom, every stock car @ stock boost would have stuck primaries.

Why you want to run 50psi base fuel pressure, I do not know. This will just make the car more difficult to tune.

Most aftermarket rails are set up to accept 3/8 NPT fittings, with an inside diameter of .66" (17mm). You would need to tap the stock rail to use it. It would need to be machined to accept the 850cc primaries, whoever you use to do this would have the capabilities to tap the rail. Or you could just install top feed injectors and primary rail.

http://banzai-racing.com/store/fuel_rails.html

 

How much power are you realistically looking to make? While I agree with most of what Banzai stated, unless you're looking to make some serious power -6 all around should be sufficient. The returning fuel is under little or no pressure so there is no need to use -8 line. It won't hurt to use -8 but I'm just saying it's probably unnecessary.

-Dan

 

ok, im gonna buy 2 305ltr fuel pumps and run one fuel line down to the front of the car, these need to be able to supply up to 6000cc/min when the engine is flat out.

I wanted to fit the pumps and run some fuel lines then fit everything else when i have more money, how would you do it?

When i said about injectors sticking i was told that above 45psi base pressure you have that problem, i did wonder about it as if the FPR is 1:1 then running 40psi base and 15psi of boost is the same as 45psi base and 10psi of boost so your working the injectors the same.......but maybe im wrong.

The reason for the high fuel pressure is to make my secondary injectors work for what they are designed for, ie, loads of fuel(2500cc per injector)

i need to make 700bhp at the flywheel to achieve my top speed target, but thats UK figures so just imagine 700whp for you guys.

ok thanks for the info about the return line

 

Just a little warning about running the stock 550's on higher fuel pressure, you'll probably have hard time getting the car started. At least that's what happened on my car when I ran 550cc / 1000cc (Bosch EV14) last year. Idle pressure was about 3bars when the stock 550's started to have hard time. Don't know if my injectors started to leak or they just couldn't handle the higher pressure, didn't bother to find out since I could start the car every time this way:

When I started the car I had to rise the pressure by turning the pump on, then shut the pump and started cranking, when the car started I turned the pump back on.

This year I'll be running those Bosch 1000cc's as primary and ID2200 secondary with two fuel pressure regulators, one for primary and one for secondary rail. Hopefully I'll be able to start the car normally now

btw, what is your top speed target?

 

"Why you want to run 50psi base fuel pressure, I do not know. This will just make the car more difficult to tune."





Why?

Obviously you have never done it otherwise you would not say that!

There is nothing wrong with running higher base fuel pressures to achieve higher flow rates out of the injectors.

 

Running 550cc primary and 2200cc secondarys will make smooth staging difficult.

My advice for the fuel line plumbing would be -8 feed to a Y into Two -6 which feed each rail and on the return use both ports on FPR to a -6 return.
Dont go silly with pump volume either as fuel temps will rise dramaticly. Once you have used the fuel past peak power it is used for thermal management. Which is why tuners run turbo engines rich. Having fuel close to boiling does not help with charge cooling and with tuning rotarys you need lots

 

So, a few things to consider since I was in the same boat myself and had had to decide what to do.

So the big question I ran into with my twin denso pump setup was: What happens if one pump goes out (dies, blows a fuse, etc.. quite a possible scenario)? Because if you tune around having two pumps pumping, and one goes out, you will have no idea (even if you have a fuel pressure gauge) UNTIL you push the fuel system and the pressure drops, you lean out, and possibly blow your motor . Personally I ran two denso pumps instead of one larger pump to keep the noise down as it's a street car.

The solution I came up with and am currently using is an independent parallel pump setup (I'm interested to see what others think ). I'm running each pump -6 to its own filter, and to two separate hard lines (use the vapor line as a 2nd fuel line). When the fuel reaches the engine bay I run each hard line to -6 lines INDEPENDANTLY to each fuel rail which (still separate) connects to an aeromotive -6 pressure regulator with two input ports. The fuel meets at the FPR and returns low/no pressure -6 back to the tank via the stock return line. To keep the two pumps separate during a "one pump failure" situation, I've installed one way check valves between each rail and the FPR to prevent back pressurization/flow into the other rail. So with this setup, if a pump fails, so does the associated rail. If the primary rail dies I'll know instantly as the car will die. If the secondary fails then the motor should fall on its face when I give it the beans, and I'll know something is up. Is this a fool proof method... I don't know but it sounds better to me than no safety net.

I also thought it was a good idea to cool the return fuel back into the tank as the fuel is used to cool the pumps, and I have an extra pump in there. I added a heat sink fin cooler after the hard line return but before the tank.

|Pump 1|-------|Filter1|----------------| Primary Rail |-------|-check->>|------|Aeromotive|_____{fin cooler}_____TANK
|Pump 2|-------|Filter2|----------------|Secondary Rail|-----|-check->>|------| F P R |

 

another person mentioned about problems with big fuel pressure on stock primarys and mentioned the cheapest way is to install the 850cc out of the second rail as its a cheap way of doing it.

My target speed is 200mph within 1.5miles, if you go to the single turbo section and look for europeen(spelt incorrectly) top speed and have a read of my build

I have seen the fuel coolers before and did have a think about that as the fuel will be doing alot of travelling around the system so a fuel cooler sounds a good idea, i have actually got a pc water cooling rad i thought about using as it have proper metal fittings.

I might have a think about the seperate lines but i feel that you have one rail with access to loads of fuel and another not getting enough, 80% of my fueling is being supplied from rail

 

That PC cooling radiator idea might not be a good one, considering it's probably under zero pressure when in operation. You may want to consider how much pressure that cooler can withstand. You figure your base fuel pressure is 40psi then you'll be raising that base by 1 psi for every psi of boost.....

 

i pressure tested the little rad with 3bar and couldnt get it to leak so it might be ok, it would be on the return line back to the tank, with you mentioning low pressure on the return i wasnt expecting over 3bar of pressure, if i put it on the line after the pumps im looking at up to 90psi of pressure and i wouldnt want to guarantee it for that amount!

 

I would use -8 as a minimum probably -10. you will be flowing enough fuel to justify the larger lines and more importantly it will take some load off the pumps. I would also look into 6 injectors before you run 50psi base just to meet the fuel demands with 4 injectors. Im guessing your going to be looking at 35+ psi of boost and 50 base psi pluse line losses and filters etc so the pumps will be pushing 90+ psi at a minimum, I will guess your slightly oversized pumps at 50psi will not have the jam for the fuel load at 90psi.
my advice from a guy that doesnt make 700hp. bigger pump(s), bigger lines, more injectors, and less base pressure.

 

Forgive me if someone has already pointed this out (or if this is not typically an issue when it comes to fuel sizing), but 50 PSI at the FPR is not going to be 50 PSI at the pump discharge.

I'm not sure if the pump manufacturers provide this sort of data, but I would request getting a pump curve before selecting these pumps. Given peak design flow, calculate the pressure drop associated with the flow across all of those lines and fittings, and determine the actual discharge pressure required at the outlet of each pump. Then go to the pump curve and determine what your actual flow rate is going to be.... depending on pump characteristic, you may be surprised by the results...

Does anyone have friction losses and equivalent linear tube/pipe distance per fitting that this guy can use as a baseline?

I would also avoid immediately Wying the two pumps together... might be better to give them a little bit of straight run and then wye.